Biology

Best of Benthics

In a cold, snow-covered Quebec City, some of the best and brightest in the field of marine biology gathered to share their latest research (and a few beers) at the Benthic Ecology Meeting. Over the course of three days, over 250 talks (as well as a number of posters) were given by faculty, post-docs, graduate students, and undergraduates from universities and research institutes around the country and even some internationally. They covered topics like community ecology, anthropogenic impacts, larval ecology, conservation, invasion biology, genetic diversity, and everything in between. Fueled by several coffee breaks, I was able to attend about a quarter of these talks. Here, I have put together my Top 5 highlights from the meeting.

Over-fishing and its resulting suite of indirect effects in Caribbean reefs have led to the belief that seaweeds are thriving and taking over corals. However, it’s the interaction between reef sponges and corals that is causing the most damage. Over-fished reefs devoid of sponge eating fish result in a 3X increase of sponge overgrowth of corals. Sponges are competing with corals in over one-quarter of the reef habitat. By removing the fish, sponges of all types start to grow unchecked. However, in these same habitats seaweeds don’t appear to be taking over. Protecting reef fish is necessary for keeping the coral-sponge competition low, and keeping communities diverse and functioning.

Kelps need a good amount of water motion to perform at it’s best (Seaweed Industry).

Kelp growth and productivity is usually tied to three main environmental factors: light, nutrients, and temperature. However, water motion and waves might be just as important. Lab-grown kelp gametophytes (the gamete producing phase of this seaweed) were brought to the field in four different locations, all with different levels of wave exposure and water motion. Kelps were placed at a range of heights in the water column to test different depths. After several months, it was found that kelps exposed to the greatest amount of water motion grew significantly more than kelps at the lowest level of water motion exposure. While temperature, light, and nutrients were consistent among sites, wave motion was not, suggesting that this is an important environmental factor for kelps.

A ghost trap can still catch and ultimately kill spiny lobsters (Florida DEP).

Spiny lobsters are an important fishery in Florida, but with heavy boating traffic and storms, many spiny lobster traps are lost each year. These lost traps are called “ghost traps.” These traps are designed to take advantage of the lobster’s behavior of congregating with other lobsters in a relatively hidden area. So even after the traps are lost, they still trap spiny lobsters for up to a year after they are lost. Studying protein in the blood between trapped and untrapped lobsters has shown that trapped lobsters have a significantly lower nutritional condition and many eventually die. It was estimated over 600,000 spiny lobsters die in ghost traps in the Florida Keys alone.

Natural climate cycles like ENSO (El Nino Southern Oscillation) can be useful tools for investigating the impact of climate change on marine communities. Over a 16 year period, researchers monitored benthic communities in the rocky subtidal habitats off the Galapagos Islands. During this period two major coral bleaching events were observed and tied to an El Nino phase and a La Nina phase (respectively) which was categorized by highly variable water temperatures. We typically think of bleaching events as a sign of doom for an ecosystem, but what was found was quite the opposite. Large barnacles were able to utilize the space once occupied by the corals, and as a result attracted a large number of barnacle predators. So while corals faded, the ecosystem flourished via the bottom-up effects from the increase in barnacles.

A cross-section of a clam shell, arrows indicate reference lines where the environment has a visible imprint (James Scourse, University of Wales).

With climate change dominating the scientific conversation, the fields of paleoceanography and paleoclimatology have used the past to help explain the future. In the artic, there are few high-resolution and continuous records of marine conditions, like temperature, salinity, and oxygen concentration. The clam Artica islandica may help provide insight into past environmental conditions and large-scale ocean climate variability. This clam is extremely long-lived, with many individuals living up to 400 years old. Similar to counting rings on a tree, the shell of this clam has clear indicators of age as well as environment. Researchers found a strong correlation with shell growth and sea surface temperatures for a 100 year period. This relationship could be used to gain high-resolution climate data on the century scale, allowing us to paint a very precise picture of past marine climate.

This list is clearly just a small sample of the interesting work presented at this meeting (including presentations by other oceanbites writers!), but hopefully it serves to show the breadth and scope of the research being done by those in the field. Check out the #benthics2015 or #BEM2015 on twitter and Instagram for another look at the conference as provided by its attendees.

I am currently a postdoc at Keck Sciences, Claremont McKenna College. I work with Dr. Sarah Gilman, measuring and modeling energy budgets in intertidal species. I am a climate scientist and marine community ecologist and my PhD (University of Rhode Island) focused on how ocean acidification and eutrophication, alters coastal trophic interactions and species assemblages.